The present invention relates to an apparatus and method for preventing free flow during enteral or parenteral administration of solutions through the tubing of an infusion line. More particularly, the present invention relates to a device that can be associated with an infusion pump for delivery of a fluid to a subject wherein the device includes an anti-flow valve mechanism such that, when the device is associated with an infusion pump, fluid is allowed to flow through the tubing, and when removed from the pump the anti-flow valve closes off the tubing to prevent the undesirable free-flow of solution therethrough.
The use of infusion sets to administer solutions to patients is well known in the medical arts. Infusion sets are used for both enteral and parenteral applications. Enteral feeding pumps are used to provide patients with nutrition and medication when they are unable, for a variety of reasons, to eat normally. Parenteral (intravenous) solutions are provided to patients to ensure adequate hydration and to provide needed nutrients, minerals and medication. Often, the infusion set is placed in a free standing arrangement in which gravity forces the solution into the patient. To prevent this, the tubing is often clamped or otherwise blocked to prevent such flow when not desired.
In many medical applications, fluids must be administered to a subject in a well regulated manner. In such instances, a free-standing infusion arrangement, where fluids are delivered to the patient under the force of gravity, is not acceptable. Instead the fluids are administered through the use of an infusion pump. An infusion pump is used to regulate the amount and rate at which the fluid is delivered from a reservoir to the patient. Typically a tube connected to the reservoir passes through the infusion pump and is intravenously inserted into the patient. While the tubing from the reservoir is in the infusion pump, free flow of the fluid is restricted by the pressure of the pump mechanism rollers closing off the tubing, however, when the tubing is removed from the pump, this pressure is released and fluid flow may resume under gravity. Devices that suffer from this disadvantage are those which lack a flow control mechanism. To prevent such free-flow of fluids, multiple means of closing the tubing off when it is not inserted in a pump have been disclosed in the prior art. These devices can be manually operated clamps, or cassettes with some form of automatic flow control mechanism.
For proper operation, the clamped or otherwise blocked tubing must be manipulated so that it allows fluid flow therethrough. It is not uncommon, however, for emergencies or other distractions to prevent the medical personnel from properly loading or unloading infusion sets into the feeding pump. When the infusion set is not properly loaded in the pump or is improperly removed and the tubing is opened to allow fluid flow, a free-flow situation often develops, wherein an amount of solution that is many times the desired dose can be supplied to the patient within a relatively short time period. This can be particularly dangerous if the solution contains potent medicines or if the patient's body is not physically strong enough to adjust to the large inflow of solution.
Numerous devices have been developed in an attempt to prevent free flow conditions. Such devices, however, typically add significantly to the overall cost of the infusion set and some provide only marginal protection against free flow. Furthermore, some of these are complicated making it difficult for medical personnel to properly operate them.
One attempted simplification of such systems is the use of an infusion cassette that is only operable to allow fluid flow through the tubing when the cassette is inserted into the pump. Cassette devices of the types like those disclosed in U.S. Pat. No. 5,904,668 to Hyman et al., and U.S. Pat. No. 6,165,154 to Gray et al. tend to be more complex and require the action of additional associated mechanisms, such as the movement or closing of an infusion pump door, handle or the like to function fully.
Thus, there is a need for infusion pumps and cassettes that provide improved performance over the art in that they need to be less complex and easier to use to quickly and conveniently control the delivery of fluids to the patient. The present invention now satisfies this need.